1. Field of the Invention
This invention relates generally to cardiopulmonary support equipment, and more particularly, to intra-aortic balloon pumping devices and methods in which a working fluid is used to selectively inflate and deflate two or more intra-aortic balloons.
2. Description of the Related Art
Intra-aortic balloon catheters are used to reduce the burden on a still-beating heart, or to force blood to flow to the arteries, for example, the coronary arteries which are not receiving an adequate blood supply.
Intra-aortic balloon catheters typically consist of an intra-aortic balloon ("IAB"), an extension catheter and a connecting catheter which joins the balloon and the extension catheter. The extension catheter, connecting catheter and balloon are in fluid communication so that forcing gas through the connecting catheter causes the IAB to inflate and removing gas through the connecting catheter caused the IAB to deflate.
IAB catheters can be positioned in a patient's body using minimally-invasive catheterization procedures, rather than surgery. Typically, the furled intra-aortic balloon is inserted through a puncture wound in the groin into the patient's femoral artery and is advanced until it is disposed within the patient's descending aorta. Now the heart can be assisted by inflating and deflating the IAB in counterpulsation to the beating heart.
In designing IABs, a consideration is the benefits of minimizing the size of the wrapped membrane of the balloon which dictates the minimum size of the catheter that has to close off the puncture site in the femoral artery following the wrapped balloon membrane passage. The catheter should also be large enough to allow for the fast passage of gas, heretofore, described. All this usually causes limitation in the design and benefit to the patient.
First of all, certain percentage of LAB patients have atherosclerotic disease in their femoral and iliac arteries. That may lead to partial or near total occlusion of these vessels. That, in turn, may cause difficulties with inserting of an IAB and could provoke limb ischemia due to restricted distal blood flow. Similar complication may occur in smaller patients without this disease. It is estimated that 10-15% of IAB patients suffer from limb ischemia. Some patients are even completely denied the benefits of IAB therapy because of insertion difficulties.
A second problem is the removal of the IAB at the end of the procedure. A typical catheter has an OD of 9 to 10 Fr. After IAB removal, a clinician has to stop arterial bleeding which may not be a simple task. Pressure is usually applied to the groin area of the patient for several hours which is uncomfortable for the patient and present a constant risk of massive bleeding. Reduction of the OD of the inserted device from say 10 Fr or 11.5 Fr in the case of present insertion using a sheath to say 6 or 8 Fr will significantly improve hemostasis as known from PTCA and angiography procedures which use a smaller catheter and have a reduced time to hemostasis after the removal of the catheter.
Still another limitation of IAB therapy is the inability of the patient to move while receiving the IAB therapy. The reason for this is that movement often causes kinking of the IAB catheter which normally does not occur when small catheters, such as those used in PTCA and angiography are used.
Finally, the overall balloon volume of a catheter is limited by only a few standard volumes being presently offered for use.
An object of the present invention is therefore to overcome the various previously stated problems of the prior art by providing:
a. Smaller OD balloons to reduce the size of the insertion puncture; PA1 b. An ability to mix and match different volume size balloons to obtain the exact volume needed without having to stock numerous sizes of balloons to obtain the proper volume, and PA1 c. Reducing the overall OD of the total catheter in order to facilitate the insertion of the catheter into arteries that are restricted in size for one reason or another while allowing for the maximum flow of blood through said arteries when the catheter is in place.